Hydrogen absorption and desorption kinetics of MgH2 catalyzed by MoS2 and MoO2

Abstract The catalytic effect of MoS 2 and MoO 2 on the hydrogen absorption/desorption kinetics of MgH 2 has been investigated. It is shown that MoS 2 has a superior catalytic effect over MoO 2 on improving the hydrogen kinetic properties of MgH 2 . DTA results indicated that the desorption temperature decreased from 662.10 K of the pure MgH 2 to 650.07 K of the MgH 2 with MoO 2 and 640.34 K of that with MoS 2 . Based on the Kissinger plot, the activation energy of the hydrogen desorption process is estimated to be 101.34 ± 4.32 kJ mol −1 of the MgH 2 with MoO 2 and 87.19 ± 4.48 kJ mol −1 of that with MoS 2 , indicating that the dehydriding process energy barrier of MgH 2 can be reduced. The enhancement of the hydriding/dehydriding kinetics of MgH 2 is attributed to the presence of MgS and Mo or MgO and Mo which catalyze the hydrogen absorption/desorption behavior of MgH 2 . The detailed comparisons between MoS 2 and MoO 2 suggest that S anion has superior properties than O anion on catalyzing the hydriding/dehydriding kinetics of MgH 2 .